Field of the Invention
This invention relates generally to security systems for residential and commercial structures and, more particularly, to burglar alarm devices for closures such as windows, sliding doors, and the like. Specifically, the present invention relates to an improved burglar alarm having more than one activation mode for use with movable closures.
Description of the Prior Art
Security systems for homes and offices are quite varied and diverse and range from extremely sophisticated and expensive electronic systems to simple locking mechanisms and the like. The degree of security provided by any particular device or system is somewhat related to the sophistication and expense of the system. For many residential uses, a complete security system for doors, windows and other entry points is frequently cost-prohibitive for the average consumer. However, the number of residential burglaries has continuously increased over the years leading to a greater consumer need and demand for such systems. Thus, there is a need for simplified burglar alarms or security systems which are easy to use and inexpensive to manufacture and purchase.
Bar or stick alarms for closures having movable members, such as sliding doors and windows, are well known in the art. Examples of such devices are illustrated in U.S. Pat. Nos. 3,797,005, 4,193,067, 4,472,709, 4,495,486 and 4,553,134. Devices such as those illustrated in these prior art references, include bars or rods which are placed between a stationary window jamb or door frame and an edge of the slidable, moving member. When the movable member of the closure is then opened, a plunger or similar type of mechanism projecting from the rod is struck by the movable member and closes an electrical circuit, thereby activating an alarm.
While such devices are relatively effective and simple to install, there are several disadvantages with the systems disclosed in these references. One such disadvantages is that a burglar or intruder can break the closure glass and simply detach the burglar alarm stick without activating it. Once the stick has been detached from the movable member, the intruder can pry the movable closure member open and gain entry to the residence or office. Hence, there is no alarm mode for unauthorized or inadvertent removal of the alarm stick from its position against the closure. In addition, the devices as disclosed in these references include rather sophisticated plunger circuitry as well as some complex alarm mechanisms. Thus, there remains a distinct need in the home security field for a simplified burglar alarm for residences and offices which can operate in more than one activation mode, is simple in design and use, and is inexpensive.